Page:Popular Science Monthly Volume 1.djvu/690

674 some unknown law, a law perhaps not of a meteorological but of an astronomical origin.

We should remember, however, the imperfections and probable errors of the old tables. In former times due care was not taken in the construction and verification of the thermometers. Making every allowance for this, we may perhaps admit that the conclusion at which we have arrived cannot be very far from the truth.



HAT can there be interesting in that commonplace, repulsive little creature, which infests our houses, annoys us by its presence, and shocks our sense of decency with its filthy webs—in that cruel little monster, whose whole life is employed in weaving snares to entrap unwary flies; lying in wait for them in dark, damp corners of crevices, murdering them remorselessly when they are caught in its toils, and then sucking their life's-blood? The house-spider, indeed! Why, we sweep it from the very face of Nature wherever we find it, together with its chamber of horrors; and it must indeed be some strong temptation that would induce one to defile one's hands by contact with a creature the very idea of which suffices to inspire terror and disgust."

It is true that spiders are not very lovable creatures, but this is a prejudiced statement. Spiders are only repulsive as long as we are ignorant of them. If we will but stop to observe their wonderful structure and their ingenious ways, we shall quickly get rid of these foolish notions, and find that the creature will richly repay us for the time and pains of studying it. Spiders have a great deal of character, and, although very savage, they have also much in common with the vaunted heads of creation. Let us consider some of their peculiarities.

Spiders were formerly classed as insects, and they are commonly so regarded still, but this is an error. Insects have but six legs, while spiders have eight; there is a division in insects between the head and the trunk, but spiders have no separate head, the head and thorax being fused together, under the name of cephalothorax. In many kinds, body, thorax, and abdomen, are so closely merged together that their parts cannot be traced. Again, insects undergo metamorphoses or transformations in their growth, while spiders do not. They belong to a group which includes mites and scorpions, and is named the Arachnida. There are multitudes of different kinds, and they vary in dimensions from the size of a grain of sand to several inches in diameter. Some spiders are met with in all parts of the world, and some are limited to special localities; some live in the fields, and others on the water; some dwell habitually in houses, and others are driven in by